GitLab

* clib.rom_link_v doesn't seem to have been kept in step with the changes
  to srcbuild as part of the cross-compilation work: it is no longer the
  job of the verbatim rom link makefie fragment to provide a rom_link rule.
  An appropriate alternative set of forwarding rules have been implemented
  instead.
* clib.rom_link_v was never taught about the new C99 library chunks, and the
  relevant s files weren't being exported in the BBE phase either.

Retagged since this won't affect code generation for existing builds.

Detail:
  The BBE export rules for this component are fairly complex.  The rom_link
    bbe rule is overridden in its entirety by clib.rom_link_v as the symbol
    definitions need to be generated and exported during the rom_link phase.
Admin:
  Tested in BBE build; does not affect other builds.

Version 5.26. Tagged as 'RISC_OSLib-5_26'